Field of the Invention
The invention relates to a sliver can transport system, having a can vehicle for transporting sliver cans and traveling between a can delivery station, work stations of at least one sliver-processing textile machine, and a discharge station for empty cans, a loading and unloading device for sliver cans on the can vehicle, and a positioning device for positioning the can vehicle relative to parking places of the cans.
Many proposals are already known from the prior art to automate the supplying of sliver cans to sliver-processing textile machines, or in other words to automate the transport of sliver cans between a can delivery station, the work stations of the textile machine, and a discharge station for the empty cans. For instance, German Utility Model DE-GM 88 12 622 discloses a device for changing the sliver cans of a spinning machine. The sliver cans are so-called rectangular cans, which are longer than they are wide. They have approximately the same width as a spinning station and thus supply only the spinning station located above them. Therefore, the change of sliver cans can be effected at each spinning station without interrupting the course of work at adjacent spinning stations. In order to allow the sliver cans to be set down in a precise alignment with the spinning stations, the parking places are separated from one another by ribs. In the longitudinal direction, the insertion of the sliver cans is limited by stops. A can transport vehicle that is known from German Published, Non-Prosecuted Application DE 43 23 726 A1, corresponding to U.S. application Ser. No. 08/276,168, filed Jul. 15, 1994, now U.S. Pat. No. 5,511,372, has a changing mechanism adapted to rectangular cans and is capable of performing a positionally accurate can change. The changing mechanism for the sliver cans is suited to picking up empty sliver cans and setting them down on the can transport vehicle and to setting down filled sliver cans, positionally accurately, below the spinning stations.
As the aforementioned references disclose, sliver ends are prepared for automatic insertion into the spinning stations, and are therefore positioned at a defined location on the can so that they can be picked up by the automatic sliver inserters. In order to enable the sliver gripper to engage the sliver end for insertion, the sliver cans must all be aligned in such a way that the sliver ends are in the same three-dimensional position. That can be attained, however, only if the sliver cans are all in the same plane below the spinning stations of the spinning machine. Given the length of a spinning machine, where the region of the spinning stations alone can be over 40 m long, it is not possible to preclude unevenness of the floor. Therefore, stringent demands are made of the parking places for the sliver cans, in view of the required accuracy in the position of the beginning end of the sliver.
However, the demands made in terms of the accuracy of positioning which is achievable for the sliver cans to be set down are made not only of the spinning machine. The same problems as with a spinning machine exist at the can change stations, where the empty sliver cans are set down and filled and where the filled sliver cans are held ready for retrieval by the can transport vehicles.